Seamless steel pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances that can flow — liquids and gases (fluids), slurries, powders and masses of small solids.
Seamless Pipe (and tubing) is made by extruding a steel block or by drilling a solid steel bar. Next, the extrusion or the drilled steel bar is cold drawn through a dye to achieve the diameter and thickness needed. Because this process can cause mechanical hardening, sometimes the material is annealed and straightened as a final process. Seamless Pipe & Tubing is subdivided as:
Cold Drawn Seamless, or CDS, exhibits precise tolerances and a good surface finish.
Hot Finished Seamless or HFS has less critical tolerances and a somewhat scaly finish and is not as strong as CDS.
For Drawn over Mandrel, or DOM tubing, the first stages of manufacturing are identical to the ones used to make electric resistance welded tubing, but in the finishing stages the entire flash weld is taken out and the tube is cold drawn over a mandrel. A mandrel is a round object against which material can be forged or shaped. The cold-drawn process provides the tube with better dimensional tolerances, improved surface finish and the strongest weld strength achievable.
ASTM A179 is a standard specification for seamless cold-drawn low-carbon steel heat exchangers and condenser tubes. This specification covers tubes 1/8 to 3 in. [3.2 to 76.2 mm].
The A179 specification also includes minimum wall thickness, flattening test, flaring test, hardness test, hydrostatic test, and eddy current test requirements.
ASTM A179: American Society for Testing and Materials
Standard Specification for Seamless Cold-Drawn Low-Carbon Steel Heat-Exchanger and Condenser Tubes.
Application: Oil, Gas and water delivery; Refinery, Boiler and Mechanical equipment manufacturer; structure construction; drilling, ship building and etc.
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